The term "silicone oil" is used herein to designate water-insoluble silicone polymers which are applied to hair to improve its feel or appearance. Silicone oils can provide the hair with a silky, lubricious feel. They can also provide a lusterization effect. These results are obtained by coating hair strands with thin films of silicone oil. Since silicone oils are substantially water-insoluble, after application to the hair they tend to remain thereon. Silicone oil can be applied in a shampoo, or in a hair conditioner which is applied after shampooing and followed by water-rinsing. (See, for example, U.S. Pat. Nos. 4,704,272, 3,964,500, 5,034,218 and 4,387,090).
The two most common types of hair conditioning silicone oils are referred to in the International Cosmetic Ingredient Dictionary (CTFA) as "dimethicone" and "dimethiconol". Dimethicone is defined as a mixture of fully methylated linear siloxane polymers end blocked with trimethylsiloxy units. Dimethiconol is a dimethyl silicone polymer terminated with hydroxyl groups. Such hair conditioning silicone oils are relatively non-volatile liquids, which are obtainable from commercial sources in the United States and other countries. For example, silicone fluids are sold by Dow Corning Corporation, Midland, Mich. Among the silicone oils (also called fluids) supplied by Dow Corning for use in hair treating compositions is a solution of high-viscosity dimethiconol fluid in dimethicone (Dow Corning Q2-1403 Fluid).
Since silicone oils have limited solubility in water and other polar solvents, they are usually applied in the form of dispersions or emulsions. For example, in a water-based shampoo or hair conditioner, the silicone oil may be dispersed with the aid of an emulsifying agent, and the dispersion or emulsion may be stabilized by the inclusion of thickeners.
Cationic hair conditioning agents are commonly used in hair conditioning compositions, and to a lesser extent in shampoo formulations. Typically, cationic hair conditioning agents contain one or more cationic quaternary nitrogen or amido amine group, and one or more hydrophobic long chain aliphatic or silicone polymer. The cationic group can provide a degree of substantivity between the conditioning agent and hair. The long chain hydrophobic groups, which are derived from long chain fatty acids or are silicone polymers, can provide hair conditioning or hair repair functions.
The published European patent application 0 115 806 describes a hair conditioning composition containing silicone oil dispersed in water. The composition also contains dimethicone copolyol, which the Cosmetic Dictionary defines as a polymer of dimethylpolysiloxane with polyoxyethylene and/or polyoxypropylene side chains. To provide a stable emulsion, the composition is in the form of a gel vehicle, consisting of a lipid material and a cationic surfactant.
Silicone polymers having an anionic functional group, such as a phosphate or sulfate, have heretofore received only limited use in hair conditioning compositions, and are not known to have been used with silicone oil. Methods of preparation and chemical structure of sulfated silicone polymers and phosphated silicone polymers have been disclosed, respectively, in U.S. Pat. Nos. 4,960,845 and 5,070,171. The base polymer is a dimethicone copolyol since it contains a dimethylpolysiloxane chain with a side chain of polyoxyalkylene. The sulfate or phosphate group forms the terminus of the polyoxyalkylene side chains. The end hydroxyls have been converted to ester linkages to the sulfate or phosphate groups.
Hair Conditioning lotions are conventionally formulated as aqueous solutions, dispersions or emulsions. Organic solvents are not ordinarily used as carriers for the hair treating agents. Organic liquids may be included in the total formula as emulsifiers or hair conditioners. For example, U.S. Pat. No. 4,493,824 describes a water-based hair rinse containing a minor amount of polyethylene glycol.